Extended range and related intraocular lenses for presbyopia treatment

ABSTRACT

Apparatuses, systems and methods for providing improved ophthalmic lenses, particularly intraocular lenses (IOLs), include features for reducing dysphotopsia effects, such as haloes and glare, in extended range of vision lenses. Exemplary ophthalmic lenses can include a central zone with a first set of three echelettes arranged around the optical axis, the first set having a profile in r-squared space. An intermediate zone includes a second set of three echelettes arranged around the optical axis, the second set having a profile in r-squared space that is different than the profile of the first set. A peripheral zone includes a third set of three echelettes arranged around the optical axis, the third set having a profile in r-squared space that is different than the profile of the first set and the profile of the second set.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. ProvisionalApplication No. 62/526,094, filed Jun. 28, 2017, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND

Embodiments of the present invention relate to vision treatmenttechniques and in particular, to ophthalmic lenses such as, for example,contact lenses, corneal inlays or onlays, or intraocular lenses (IOLs)including, for example, phakic IOLs and piggyback IOLs (i.e. IOLsimplanted in an eye already having an IOL).

Presbyopia is a condition that affects the accommodation properties ofthe eye. As objects move closer to a young, properly functioning eye,the effects of ciliary muscle contraction and zonular relaxation allowthe lens of the eye to change shape, and thus increase its optical powerand ability to focus at near distances. This accommodation can allow theeye to focus and refocus between near and far objects.

Presbyopia normally develops as a person ages, and is associated with anatural progressive loss of accommodation. The presbyopia eye oftenloses the ability to rapidly and easily refocus on objects at varyingdistances. The effects of presbyopia usually become noticeable after theage of 45 years. By the age of 65 years, the crystalline lens has oftenlost almost all elastic properties and has only a limited ability tochange shape.

Along with reductions in accommodation of the eye, age may also induceclouding of the lens due to the formation of a cataract. A cataract mayform in the hard central nucleus of the lens, in the softer peripheralcortical portion of the lens, or at the back of the lens. Cataracts canbe treated by the replacement of the cloudy natural lens with anartificial lens. An artificial lens replaces the natural lens in theeye, with the artificial lens often being referred to as an intraocularlens or “IOL”.

Monofocal IOLs are intended to provide vision correction at one distanceonly, usually the far focus. At the very least, since a monofocal IOLprovides vision treatment at only one distance and since the typicalcorrection is for far distance, spectacles are usually needed for goodvision at near distances and sometimes for good vision at intermediatedistances. The term “near vision” generally corresponds to visionprovided when objects are at a distance from the subject eye at equal;or less than 1.5 feet. The term “distant vision” generally correspondsto vision provided when objects are at a distance of at least about 5-6feet or greater. The term “intermediate vision” corresponds to visionprovided when objects are at a distance of about 1.5 feet to about 5-6feet from the subject eye. Such characterizations of near, intermediate,and far vision correspond to those addressed in Morlock R, Wirth R J,Tally S R, Garufis C, Heichel C W D, Patient-Reported SpectacleIndependence Questionnaire (PRSIQ): Development and Validation. Am JOphthalmology 2017; 178:101-114.

There have been various attempts to address limitations associated withmonofocal IOLs. For example, multifocal IOLs have been proposed thatdeliver, in principle, two foci, one near and one far, optionally withsome degree of intermediate focus. Such multifocal, or bifocal, IOLs areintended to provide good vision at two distances, and include bothrefractive and diffractive multifocal IOLs. In some instances, amultifocal IOL intended to correct vision at two distances may provide anear (add) power of about 3.0 or 4.0 diopters.

Multifocal IOLs may, for example, rely on a diffractive optical surfaceto direct portions of the light energy toward differing focal distances,thereby allowing the patient to clearly see both near and far objects.Multifocal ophthalmic lenses (including contact lenses or the like) havealso been proposed for treatment of presbyopia without removal of thenatural crystalline lens. Diffractive optical surfaces, either monofocalor multifocal, may also be configured to provide reduced chromaticaberration.

Diffractive monofocal and multifocal lenses can make use of a materialhaving a given refractive index and a surface curvature which provide arefractive power. Diffractive lenses have a diffractive profile whichconfers the lens with a diffractive power that contributes to theoverall optical power of the lens. The diffractive profile is typicallycharacterized by a number of diffractive zones. When used for ophthalmiclenses these zones are typically annular lens zones, or echelettes,spaced about the optical axis of the lens. Each echelette may be definedby an optical zone, a transition zone between the optical zone and anoptical zone of an adjacent echelette, and an echelette geometry. Theechelette geometry includes an inner and outer diameter and a shape orslope of the optical zone, a height or step height, and a shape of thetransition zone. The surface area or diameter of the echelettes largelydetermines the diffractive power(s) of the lens and the step height ofthe transition between echelettes largely determines the lightdistribution between the different powers. Together, these echelettesform a diffractive profile.

A multifocal diffractive profile of the lens may be used to mitigatepresbyopia by providing two or more optical powers; for example, one fornear vision and one for far vision. The lenses may also take the form ofan intraocular lens placed within the capsular bag of the eye, replacingthe original lens, or placed in front of the natural crystalline lens.The lenses may also be in the form of a contact lens, most commonly abifocal contact lens, or in any other form mentioned herein.

Although multifocal ophthalmic lenses lead to improved quality of visionfor many patients, additional improvements would be beneficial. Forexample, some pseudophakic patients experience undesirable visualeffects (dysphotopsia), e.g. glare or halos. Halos may arise when lightfrom the unused focal image creates an out-of-focus image that issuperimposed on the used focal image. For example, if light from adistant point source is imaged onto the retina by the distant focus of abifocal IOL, the near focus of the IOL will simultaneously superimpose adefocused image on top of the image formed by the distant focus. Thisdefocused image may manifest itself in the form of a ring of lightsurrounding the in-focus image, and is referred to as a halo. Anotherarea of improvement revolves around the typical bifocality of multifocallenses. While multifocal ophthalmic lenses typically provide adequatenear and far vision, intermediate vision may be compromised.

A lens with an extended range of vision may thus provide certainpatients the benefits of good vision at a range of distances, whilehaving reduced or no dysphotopsia. Various techniques for extending thedepth of focus of an IOL have been proposed. For example, someapproaches are based on a bulls-eye refractive principle, and involve acentral zone with a slightly increased power. Other techniques includean asphere or include refractive zones with different refractive zonalpowers.

Although certain proposed treatments may provide some benefit topatients in need thereof, further advances would be desirable. Forexample, it would be desirable to provide improved IOL systems andmethods that confer enhanced image quality across a wide and extendedrange of foci without dysphotopsia. Embodiments of the present inventionprovide solutions that address the problems described above, and henceprovide answers to at least some of these outstanding needs.

BRIEF SUMMARY

Embodiments herein described include ophthalmic lenses with a firstsurface and a second surface disposed about an optical axis, and adiffractive profile imposed on one of the first surface or the secondsurface. The diffractive profile may include a central zone, aperipheral zone, and an intermediate zone positioned between the centralzone and the peripheral zone. The central zone may include a first setof three echelettes arranged around the optical axis, the first sethaving a profile in r-squared space. The intermediate zone may include asecond set of three echelettes arranged around the optical axis, thesecond set having a profile in r-squared space that is different thanthe profile of the first set. The peripheral zone may include a thirdset of three echelettes arranged around the optical axis, the third sethaving a profile in r-squared space that is different than the profileof the first set and the profile of the second set, the third set beingrepeated in series on the peripheral zone.

Embodiments herein described include ophthalmic lenses with a firstsurface and a second surface disposed about an optical axis, and adiffractive profile imposed on one of the first surface or the secondsurface. The diffractive profile includes a central zone, a peripheralzone, and an intermediate zone positioned between the central zone andthe peripheral zone. The central zone includes a first set of threeechelettes arranged about the optical axis, the first set including azero step height between two of the three echelettes of the first set.The intermediate zone includes a second set of three echelettes arrangedabout the optical axis. The peripheral zone includes a third set ofthree echelettes arranged about the optical axis, the third setincluding a zero step height between two of the three echelettes of thethird set, the third set being repeated in series on the peripheralzone.

Embodiments herein described include ophthalmic lenses with a firstsurface and a second surface disposed about an optical axis, and adiffractive profile imposed on one of the first surface or the secondsurface. The diffractive profile includes a central zone and aperipheral zone. The central zone includes a first set of threeechelettes arranged around the optical axis, the first set having aprofile in r-squared space. The peripheral zone includes a second set ofthree echelettes arranged around the optical axis, the second set beingrepeated in series on the peripheral zone and having a profile inr-squared space that is different than the profile of the first set.

Embodiments herein described also include manufacturing systems formaking an ophthalmic lens. Such manufacturing system can include aninput that accepts an ophthalmic lens prescription for a patient eye. Afirst module is configured to generate a diffractive profile based onthe ophthalmic lens prescription. The diffractive profile includes acentral zone, a peripheral zone, and an intermediate zone positionedbetween the central zone and the peripheral zone. The central zoneincludes a first set of three echelettes arranged around an opticalaxis, the first set having a profile in r-squared space. Theintermediate zone includes a second set of three echelettes arrangedaround the optical axis, the second set having a profile in r-squaredspace that is different than the profile of the first set. Theperipheral zone includes a third set of three echelettes arranged aroundthe optical axis, the third set having a profile in r-squared space thatis different than the profile of the first set and the profile of thesecond set, the third set being repeated in series on the peripheralzone. The manufacturing system includes a manufacturing assembly thatfabricates the ophthalmic lens based on the diffractive profile.

Embodiments herein described also include manufacturing systems formaking an ophthalmic lens. Such manufacturing system can include aninput that accepts an ophthalmic lens prescription for a patient eye. Afirst module is configured to generate a diffractive profile based onthe ophthalmic lens prescription. The diffractive profile includes acentral zone and a peripheral zone. The central zone includes a firstset of three echelettes arranged around an optical axis, the first sethaving a profile in r-squared space. The peripheral zone includes asecond set of three echelettes arranged around the optical axis, thesecond set being repeated in series on the peripheral zone and having aprofile in r-squared space that is different than the profile of thefirst set. The manufacturing system includes a manufacturing assemblythat fabricates the ophthalmic lens based on the diffractive profile.

Embodiments herein described also include methods of designing anintraocular lens. Such methods can include defining a diffractiveprofile and generating a diffractive lens surface based on thediffractive profile. The diffractive profile may include a central zone,a peripheral zone, and an intermediate zone positioned between thecentral zone and the peripheral zone. The central zone includes a firstset of three echelettes arranged around the optical axis, the first sethaving a profile in r-squared space. The intermediate zone includes asecond set of three echelettes arranged around the optical axis, thesecond set having a profile in r-squared space that is different thanthe profile of the first set. The peripheral zone includes a third setof three echelettes arranged around the optical axis, the third sethaving a profile in r-squared space that is different than the profileof the first set and the profile of the second set, the third set beingrepeated in series on the peripheral zone.

Embodiments herein described also include methods of designing anintraocular lens. Such methods can include defining a diffractiveprofile and generating a diffractive lens surface based on thediffractive profile. The diffractive profile may include a central zoneand a peripheral zone. The central zone includes a first set of threeechelettes arranged around an optical axis, the first set having aprofile in r-squared space. The peripheral zone includes a second set ofthree echelettes arranged around the optical axis, the second set beingrepeated in series on the peripheral zone and having a profile inr-squared space that is different than the profile of the first set.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a cross-sectional view of an eye with an implantedmultifocal refractive intraocular lens;

FIG. 1B illustrates a cross-sectional view of an eye having an implantedmultifocal diffractive intraocular lens;

FIG. 2A illustrates a front view of a diffractive multifocal intraocularlens;

FIG. 2B illustrates a cross-sectional view of a diffractive multifocalintraocular lens;

FIGS. 3A-3B are graphical representations of a portion of thediffractive profile of a conventional diffractive multifocal lens;

FIG. 4 is a graphical representation illustrating a lens profile for adiffractive lens according to certain embodiments of this disclosure;

FIG. 5 is a graphical representation illustrating a lens profile for adiffractive lens according to certain embodiments of this disclosure;

FIG. 6 is a simplified block diagram illustrating a system forgenerating a diffractive lens surface, in accordance with embodiments;

FIG. 7 illustrates an example process for generating a diffractive lenssurface; and

FIG. 8 illustrates an example computing environment for facilitating thesystems and processes of FIGS. 6 and 7.

DETAILED DESCRIPTION

Contemporary Lens Shapes and Diffractive Profiles

FIGS. 1A, 1B, 2A, 2B, 3A and 3B illustrate multifocal IOL lensgeometries, aspects of which are described in U.S. Patent PublicationNo. 2011-0149236 A1, which is hereby incorporated by reference in itsentirety.

FIG. 1A is a cross-sectional view of an eye E fit with a multifocal IOL11. As shown, multifocal IOL 11 may, for example, comprise a bifocalIOL. Multifocal IOL 11 receives light from at least a portion of cornea12 at the front of eye E and is generally centered about the opticalaxis of eye E. For ease of reference and clarity, FIGS. 1A and 1B do notdisclose the refractive properties of other parts of the eye, such asthe corneal surfaces. Only the refractive and/or diffractive propertiesof the multifocal IOL 11 are illustrated.

Each major face of lens 11, including the anterior (front) surface andposterior (back) surface, generally has a refractive profile, e.g.biconvex, plano-convex, plano-concave, meniscus, etc. The two surfacestogether, in relation to the properties of the surrounding aqueoushumor, cornea, and other optical components of the overall opticalsystem, define the effects of the lens 11 on the imaging performance byeye E. Conventional, monofocal IOLs have a refractive power based on therefractive index of the material from which the lens is made, and alsoon the curvature or shape of the front and rear surfaces or faces of thelens. One or more support elements may be configured to secure the lens11 to a patient's eye.

Multifocal lenses may optionally also make special use of the refractiveproperties of the lens. Such lenses generally include different powersin different regions of the lens so as to mitigate the effects ofpresbyopia. For example, as shown in FIG. 1A, a perimeter region ofrefractive multifocal lens 11 may have a power which is suitable forviewing at far viewing distances. The same refractive multifocal lens 11may also include an inner region having a higher surface curvature and agenerally higher overall power (sometimes referred to as a positive addpower) suitable for viewing at near distances.

Rather than relying entirely on the refractive properties of the lens,multifocal diffractive IOLs or contact lenses can also have adiffractive power, as illustrated by the IOL 18 shown in FIG. 1B. Thediffractive power can, for example, comprise positive or negative power,and that diffractive power may be a significant (or even the primary)contributor to the overall optical power of the lens. The diffractivepower is conferred by a plurality of concentric diffractive zones whichform a diffractive profile. The diffractive profile may either beimposed on the anterior face or posterior face or both.

The diffractive profile of a diffractive multifocal lens directsincoming light into a number of diffraction orders. As light 13 entersfrom the front of the eye, the multifocal lens 18 directs light 13 toform a far field focus 15 a on retina 16 for viewing distant objects anda near field focus 15 b for viewing objects close to the eye. Dependingon the distance from the source of light 13, the focus on retina 16 maybe the near field focus 15 b instead. Typically, far field focus 15 a isassociated with 0^(th) diffractive order and near field focus 15 b isassociated with the 1^(st) diffractive order, although other orders maybe used as well.

Bifocal ophthalmic lens 18 typically distributes the majority of lightenergy into two viewing orders, often with the goal of splitting imaginglight energy about evenly (50%:50%), one viewing order corresponding tofar vision and one viewing order corresponding to near vision, althoughtypically, some fraction goes to non-viewing orders.

Corrective optics may be provided by phakic IOLs, which can be used totreat patients while leaving the natural lens in place. Phakic IOLs maybe angle supported, iris supported, or sulcus supported. The phakic IOLcan be placed over the natural crystalline lens or piggy-backed overanother IOL. It is also envisioned that the present disclosure may beapplied to inlays, onlays, accommodating IOLs, pseudophakic IOLs, otherforms of intraocular implants, spectacles, and even laser visioncorrection.

FIGS. 2A and 2B show aspects of a conventional diffractive multifocallens 20. Multifocal lens 20 may have certain optical properties that aregenerally similar to those of multifocal IOLs 11, 18 described above.Multifocal lens 20 has an anterior lens face 21 and a posterior lensface 22 disposed about optical axis 24.

When fitted onto the eye of a subject or patient, the optical axis oflens 20 is generally aligned with the optical axis of eye E. Thecurvature of lens 20 gives lens 20 an anterior refractive profile and aposterior refractive profile. Although a diffractive profile may also beimposed on either anterior face 21 and posterior face 22 or both, FIG.2B shows posterior face 22 with a diffractive profile. The diffractiveprofile is characterized by a plurality of annular diffractive zones orechelettes 23 spaced about optical axis 24. While analytical opticstheory generally assumes an infinite number of echelettes, a standardmultifocal diffractive IOL typically has at least 9 echelettes, and mayhave over 30 echelettes. For the sake of clarity, FIG. 2B shows only 4echelettes. Typically, an IOL is biconvex, or possibly plano-convex, orconvex-concave, although an IOL could be plano-plano, or otherrefractive surface combinations.

FIGS. 3A and 3B are graphical representations of a portion of a typicaldiffractive profile of a multifocal lens. While the graph shows only 3echelettes, typical diffractive lenses extend to at least 9 echelettesto over 32 echelettes. In FIG. 3A, the height 32 of the surface reliefprofile (from a plane perpendicular to the light rays) of each point onthe echelette surface is plotted against the square of the radialdistance (r² or ρ) from the optical axis of the lens (referred to asr-squared space). In multifocal lenses, each echelette 23 may have adiameter or distance from the optical axis which is often proportionalto √n, n being the number of the echelette 23 as counted from opticalaxis 24. Each echelette has a characteristic optical zone 30 andtransition zone 31. Optical zone 30 typically has a shape or downwardslope that is parabolic as shown in FIG. 3B. The slope of each echelettein r-squared space (shown in FIG. 3A), however, is the same. As for thetypical diffractive multifocal lens, as shown here, all echelettes havethe same surface area. The area of echelettes 23 determines thediffractive power of lens 20, and, as area and radii are correlated, thediffractive power is also related to the radii of the echelettes. Thephysical offset of the trailing edge of each echelette to the leadingedge of the adjacent echelette is the step height. An exemplary stepheight between adjacent echelettes is marked as reference number 33 inFIG. 3A. The step heights remain the same in r-squared space (FIG. 3A)and in linear space (FIG. 3B). The step offset is the height offset ofthe transition zone from the underlying base curve. An exemplary stepoffset is marked as reference number 421 in FIG. 4.

Conventional multifocal diffractive lenses typically provide for nearand far vision, neglecting visual performance at intermediate distances.Providing for an extended range of vision can help to improve the visualperformance at intermediate distances. In addition, providing for azero-step height between transition zones may reduce visual artifactssuch as halos or glare that may otherwise be visible to a user due toone or more of the boundaries between the optical zones.

FIG. 4 shows a graphical representation illustrating an embodiment of adiffractive profile 400. The diffractive profile 400 may result in alens having an extended range of vision or a multifocal lens.

The diffractive profile 400, in the form of a sag profile, is shownextending outward from an optical axis 402. The diffractive zones, orechelettes, are shown extending radially outward from the optical axis402, and would be arranged around the optical axis 402 (the other halfof the diffractive profile 400 is not shown). The diffractive profile400 is shown relative to the Y axis 404, which represents the height orphase shift of the diffractive profile 400. The height is shown in unitsof micrometers, and may represent the distance from the base curve ofthe lens. In other embodiments, other units or scalings may be utilized.

The height or phase shift of the diffractive profile 400 is shown inrelation to the radius on the X axis 406 from the optical axis 402. Theradius is shown in units of millimeters, although in other embodiments,other units or scalings may be utilized. The diffractive profile 400 mayextend outward from the optical axis 402 for a radius of 3.0 millimeters(diameter of 6.0 millimeters), although in other embodiments thediffractive profile 400 may extend for a lesser or greater radius.

The diffractive profile 400 includes three sets 408, 410, 412 ofdiffractive zones or echelettes. The three sets include a first set 408positioned at a central zone 414 of the lens. The second set 410 ispositioned at an intermediate zone 416 of the lens. The third set 412 ispositioned at a peripheral zone 418 of the lens. The third set 412 maybe repeated in series on the peripheral zone 418.

The first set 408 is adjacent the optical axis 402. The first setincludes three diffractive zones or echelettes 420 a, 420 b, 420 c. Theechelettes 420 a, 420 b, 420 c are connected by transition zones 422 a,422 b. The separation between the different echelettes 420 a, 420 b, 420c, as well as the separation between the echelettes of the other sets410, 412, is indicated by the dashed step number line 424.

The first set 408 has a profile defined by the shape or slope of theechelettes 420 a, 420 b, 420 c, and the step height and step offsets (asdiscussed previously) at the transition zones 422 a, 422 b, and theheight of the first echelette 420 a at the optical axis 402, and theheight of the trailing end of echelette 420 c at the transition zone426. The first echelette 420 a of the first set 408 has a negative slopeextending from its leading end to its trailing edge or end at thetransition zone 422 a. The trailing end has a height corresponding tothe step offset at the transition zone 422 a. The leading end of thesecond echelette 420 b is separated from the trailing end of the firstechelette 420 a by the step height corresponding to the transition zone422 a.

The second echelette 420 b extends from its leading end to the trailingend at transition zone 422 b and has a negative slope. The slope of thesecond echelette 420 b may be different than the slope of the firstechelette 420 a. The trailing end of the second echelette 420 b has aheight corresponding to the step offset at the transition zone 422 b.The step offset at the transition zone 422 b is less than the stepoffset at the transition zone 422 a. The second echelette 420 bcontinuously joins with the third echelette 420 c at a zero step height.Thus, there is no step height at the transition zone 422 b. The radiusof curvature of the profile at the transition zone 422 b changeshowever. The zero step height, in any of the sets of echelettes, mayreduce visual artifacts such as halos or glare that may otherwise bevisible to a user due to one or more of the boundaries between theoptical zones.

The third echelette 420 c of the first set 408 has a leading endconnected to the second echelette 420 b at the transition zone 422 b.The third echelette 420 c has a negative slope, which may be differentthan the slope of the second echelette 420 b and the first echelette 420a. The third echelette 420 c extends to its trailing end at thetransition zone 426 between the first set 408 and the second set 410.The third echelette 420 c may have a zero step offset at the transitionzone 426.

Using the scaling shown in FIG. 4, the first set 408, and the centralzone 414, may end at the radial distance of about 0.9 millimeters.

The profiles of each of the echelettes 420 a, 420 b, 420 c, aredifferent from each other. The different profiles are due to thediffering step heights, step offsets, and slopes of each echelette 420a, 420 b, 420 c. In r-squared space (discussed previously), the profilesof the echelettes 420 a, 420 b, 420 c, are different from each other,due to the differing step heights, step offsets, and slopes of eachechelette 420 a, 420 b, 420 c.

The second set 410 of echelettes may be adjacent the first set 408 ofechelettes. The second set 410 includes three diffractive zones orechelettes 428 a, 428 b, 428 c. The echelettes 428 a, 428 b, 428 c areconnected by transition zones 430 a, 430 b.

The second set 410 has a profile defined by the shape or slope of theechelettes 428 a, 428 b, 428 c, and the step height and step offsets atthe transition zones 430 a, 430 b, 426, and the height of the trailingend of echelette 428 c at the transition zone 432. The first echelette428 a of the second set 410 connects to the first set 408 at thetransition zone 426. The transition zone 426 has a step height that islarger than any of the step heights of the first set 408. The firstechelette 428 a has a negative slope extending from its leading end toits trailing end at the transition zone 430 a. The trailing end has aheight corresponding to the step offset at the transition zone 430 a.The leading end of the second echelette 428 b is separated from thetrailing end of the first echelette 428 a by the step heightcorresponding to the transition zone 430 a. The step height of thetransition zone 430 a is less than the step height of the transitionzone 426.

The second echelette 428 b extends from its leading end to the trailingend at transition zone 430 b and has a negative slope. The slope of thesecond echelette 428 b may be different than the slope of the firstechelette 428 a. The trailing end of the second echelette 428 b has aheight corresponding to the step offset at the transition zone 430 b.The step offset at the transition zone 430 b is less than the stepoffset at the transition zone 430 a.

The third echelette 428 c of the second set 410 has a leading endconnected to the second echelette 428 b at the transition zone 430 b.The step height of the transition zone 430 b may be less than the stepheight of the transition zones 430 a and 426. The third echelette 428 chas a negative slope, which may be different than the slope of the firstechelette 428 a and the second echelette 428 b. The third echelette 428c extends to its trailing end at the transition zone 432 between thesecond set 410 and the third set 412. The third echelette 428 c may havea zero step offset at the transition zone 432. A non-zero step heightmay be between each of the echelettes of the second set 410.

Using the scaling shown in FIG. 4, the second set 410, and theintermediate zone 416, may end at the radial distance of about 1.35millimeters.

The profiles of each of the echelettes 428 a, 428 b, 428 c, aredifferent from each other. The different profiles are due to thediffering step heights, step offsets, and slopes of each echelette 428a, 428 b, 428 c. In r-squared space, the profiles of the echelettes 428a, 428 b, 428 c, are different from each other, due to the differingstep heights, step offsets, and slopes of each echelette 428 a, 428 b,428 c.

The profile of the second set 410 is different than the profile of thefirst set 408. The different profiles are due to the differing stepheights, step offsets, and slopes of the echelettes within therespective set 408, 410. In r-squared space, the profile of the secondset 410 is different than the profile of the first set 408 due to thediffering step heights, step offsets, and slopes of the echeletteswithin the respective set 408, 410.

The third set 412 of echelettes may be adjacent the second set 410 ofechelettes. The third set 412 includes three diffractive zones orechelettes 434 a, 434 b, 434 c. The echelettes 434 a, 434 b, 434 c areconnected by transition zones 436 a, 436 b.

The third set 412 has a profile defined by the shape or slope of theechelettes 434 a, 434 b, 434 c, and the step height and step offsets atthe transition zones 436 a, 436 b, 432, and the height of the trailingend of echelette 434 c at the transition zone to the next adjacent set.The first echelette 434 a of the third set 412 connects to the secondset 410 at the transition zone 432. The transition zone 432 has a stepheight that is smaller than the step height of the transition zone 426and larger than the step heights of the transition zones 422 a, 430 a,430 b. The first echelette 434 a has a negative slope extending from itsleading end to its trailing end at the transition zone 436 a. Thetrailing end has a height corresponding to the step offset at thetransition zone 436 a. The step offset at the transition zone 436 a issmaller than the step offsets of any of the first set 408 or second set410.

The leading end of the second echelette 434 b is separated from thetrailing end of the first echelette 434 a by the step heightcorresponding to the transition zone 436 a. The step height of thetransition zone 436 a is less than the step height of the transitionzone 426 and greater than the step height of the transition zones 422 a,430 a, 430 b.

The second echelette 434 b extends from its leading end to the trailingend at transition zone 436 b and has a negative slope. The slope of thesecond echelette 434 b may be different than the slope of the firstechelette 434 a. The trailing end of the second echelette 434 b has aheight corresponding to the step offset at the transition zone 436 b.The step offset at the transition zone 436 b is greater than the stepoffset at the transition zone 436 a and transition zones 422 b and 430b.

The third echelette 434 c continuously joins with the second echelette434 b at a zero step height. Thus, there is no step height at thetransition zone 436 b. The radius of curvature of the profile at thetransition zone 436 b changes however.

The third echelette 434 c of the third set 412 has a leading endconnected to the second echelette 434 b at the transition zone 436 b.The third echelette 434 c has a negative slope, which may be differentthan the slope of the second echelette 436 b and the first echelette 434a. The third echelette 436 c extends to its trailing end at the trailingend of the third set 412, and may have a zero step offset at thetrailing end of the third set 412.

The profiles of each of the echelettes 434 a, 434 b, 434 c, aredifferent from each other. The different profiles are due to thediffering step heights, step offsets, and slopes of each echelette 434a, 434 b, 434 c. In r-squared space, the profiles of the echelettes 434a, 434 b, 434 c, are different from each other, due to the differingstep heights, step offsets, and slopes of each echelette 434 a, 434 b,434 c.

The profile of the third set 412 is different than the profile of thefirst set 408 and the profile of the second set 410. The differentprofiles are due to the differing step heights, step offsets, and slopesof the echelettes within the respective set 408, 410, 412. In r-squaredspace, the profile of the third set 412 is different than the profile ofthe first set 408 and the second set 410 due to the differing stepheights, step offsets, and slopes of the echelettes within therespective set 408, 410, 412.

The third set 412 may be repeated in series on the peripheral zone 418to form a repeated set 438. The repeated third set 412 may be scaled inradial size relative to the r-squared distance from the optical axis402, as is known in the art. Thus, the step heights and step offsets ofeach set in the repeated set will remain the same, as well as thesurface area of each echelette of the set. The slope of the echelettesof each set in the repeated set will remain the same in r-squared space.As such, the profile of each repeated third set 412 remains the same inr-squared space.

The repeated set 438 may include a series of eight third sets 412, asshown in FIG. 4. In other embodiments, greater or fewer numbers of thirdsets 412 may be utilized in the repeated set 438. In one embodiment, therepeated set 438 may span the entirety of the remaining portion of thelens such that the entirety of the remaining optical zone is filled (mayextend out to a full 6 millimeter diameter). In other embodiments, therepeated set 438 may span only a portion of the lens.

The profile of each of the first nine echelettes 420 a, 420 b, 420 c,428 a, 428 b, 428 c, 434 a, 434 b, 434 c, of the diffractive profile400, have different profiles from each other. The different profiles aredue to the differing step heights, step offsets, and slopes of each ofthe first nine echelettes. In r-squared space, the profile of each ofthe first nine echelettes 420 a, 420 b, 420 c, 428 a, 428 b, 428 c, 434a, 434 b, 434 c are different from each other due to the differing stepheights, step offsets, and slopes of each of the echelettes.

The surface area of the first echelette (420 a, 428 a, 434 a) of each ofthe respective first, second, and third sets (408, 410, 412) is thesame. The surface area of the second echelette (420 b, 428 b, 434 b) ofeach of the respective first, second, and third sets (408, 410, 412) isthe same. The surface area of the third echelette (420 c, 428 c, 434 c)of each of the respective first, second, and third sets (408, 410, 412)is the same. As is apparent from FIG. 4, however the step heights andstep offsets of the echelettes in the sets (408, 410, 412) differ. Allechelettes shown in FIG. 4 have the same surface area.

The three echelettes 420 a, 420 b, 420 c of the first set 408 do notrepeat. If the echelettes 420 a, 420 b, 420 c of the first set 408 wereto repeat, then the optical characteristics may be defined by at leastfour diffractive orders corresponding to at least four diffractivepowers. The repeated first set 408 may produce four diffractive ordersthat are useful for a patient's vision, corresponding to fourdiffractive powers that are useful for a patient's vision. Thediffractive orders may include a 0^(th) order and orders 1^(st) through8^(th). The orders 2^(nd) through 5^(th) may be useful for a patient'svision. The 0^(th) and 1^(st) orders may be hyperopic (beyond far), andthe 6^(th), 7^(th), and 8^(th), may be on the myopic side.

If the first set 408 were to repeat, the repeated first set 408 maydistribute light to diffractive orders, with the following lightdistribution of incident light to each of the four diffractive orders,and the diffractive power shown in Table 1 below:

TABLE 1 Diffractive order Diffractive power Light distribution 2^(nd)2.5 D (Far) 37% 3^(rd) 3.75 D (1.25 D add) 12% 4^(th) 5.0 D (2.5 D add)18% 5^(th) 6.25 D (3.75 D add) 16%

The three echelettes 428 a, 428 b, 428 c of the second set 410 do notrepeat. If the echelettes 428 a, 428 b, 428 c of the second set 410 wereto repeat, then the optical characteristics may be defined by at leastfour diffractive orders corresponding to at least four diffractivepowers. The repeated second set 410 may produce four diffractive ordersthat are useful for a patient's vision, corresponding to fourdiffractive powers that are useful for a patient's vision. Thediffractive orders may include a 0^(th) order and orders 1^(st) through8^(th). The orders 2^(nd) through 5^(th) may be useful for a patient'svision. The 0^(th) and 1^(st) orders may be hyperopic (beyond far), andthe 6^(th), 7^(th), and 8^(th), may be on the myopic side.

If the second set 410 were to repeat, the repeated second set 410 maydistribute light to four diffractive orders, with the following lightdistribution of incident light to each of the four diffractive orders,and the diffractive power shown in Table 2 below:

TABLE 2 Diffractive order Diffractive power Light distribution 2^(nd)2.5 D (Far) 45% 3^(rd) 3.75 D (1.25 D add)  1% 4^(th) 5.0 D (2.5 D add) 1% 5^(th) 6.25 D (3.75 D add) 27%

As noted in Table 2, the light distribution to the 3^(rd) and 4^(th)diffractive order is relatively low, such that a repeated second set 410may be considered to operate similar to a bifocal diffractive profile.

The three echelettes 434 a, 434 b, 434 c of the third set 412 do repeat.The optical characteristics of the repeated set 438 may be defined by atleast four diffractive orders corresponding to at least four diffractivepowers. The repeated set 438 may produce four diffractive orders thatare useful for a patient's vision, corresponding to four diffractivepowers that are useful for a patient's vision. The diffractive ordersmay include a 0^(th) order and orders 1^(st) through 8^(th). The orders2^(nd) through 5^(th) may be useful for a patient's vision. The 0^(th)and 1^(st) orders may be hyperopic (beyond far), and the 6^(th), 7^(th),and 8^(th), may be on the myopic side.

The repeated set 438 may distribute light to four diffractive orders,with the following light distribution of incident light to each of thefour diffractive orders, and the diffractive power shown in Table 3below:

TABLE 3 Diffractive order Diffractive power Light distribution 2^(nd)2.5 D (Far) 48% 3^(rd) 3.75 D (1.25 D add)  7% 4^(th) 5.0 D (2.5 D add) 5% 5^(th) 6.25 D (3.75 D add) 15%

As noted in Table 3, the light distribution to the 3^(rd) and 4^(th)diffractive order is relatively low, such that the repeated set 438 maybe considered to operate similar to a bifocal diffractive profile. Thelight distribution of the repeated set 438 may include more than 40% ofincident light distributed toward a first diffractive power, less than10% of incident light distributed toward a second diffractive power,less than 10% of incident light distributed toward a third diffractivepower, and more than 10% of incident light distributed toward a fourthdiffractive power. The second diffractive power may be between about0.58 and 1.5 diopter, the third diffractive power may be between about1.17 and 3 diopter, and the fourth diffractive power may be betweenabout 1.75 and 4.5 diopter.

The diffractive powers and light distributions listed in each of Tables1, 2, and 3 may vary to an amount that is “about” the listed amount. Inother embodiments, the diffractive orders, powers and lightdistributions, listed in each of Tables 1, 2, and 3 may be varied asdesired.

The diffractive powers of the lens may vary, depending on the desiredperformance of the design. The diffractive powers as listed in Tables1-3 are intended for a design that provides adequate visual performanceover the entire range of vision from far to intermediate distances andnear. Lower diffractive powers may be beneficial if the desiredperformance is to emphasize good far and intermediate vision, whilevision at near distances may be slightly reduced. Such lens design mayhave a second diffractive add power of 0.58 D, a third diffractive addpower of 1.17 D and a fourth diffractive add power of 1.75 D. Someembodiments have diffractive add powers in-between these and those inTables 1-3.

The combination of the non-repeating first set 408, second set 410, andthe repeated set 438, may result in a diffractive profile producing anextended range of vision for the patient.

In one embodiment, the diffractive profile 400 may be positioned on asurface of a lens that is opposite an aspheric surface. The asphericsurface on the opposite side of the lens may be designed to reducecorneal spherical aberration of the patient.

In one embodiment, one or both surfaces of the lens may be aspherical,or include a refractive surface designed to extend the depth of focus,or create multifocality.

In one embodiment, a refractive zone on one or both surfaces of the lensmay be utilized that may be the same size or different in size as one ofthe diffractive zones. The refractive zone includes a refractive surfacedesigned to extend the depth of focus, or create multifocality.

FIG. 5 shows a graphical representation illustrating an embodiment of adiffractive profile 500. The diffractive profile 500 may result in alens having an extended range of vision or a multifocal lens.

The diffractive profile 500 is configured similarly as the diffractiveprofile 400 shown in FIG. 4. However, the diffractive profile 500includes a second set 510 of echelettes in an intermediate zone 516 thathas a profile in r-squared space that is substantially identical to theprofile of a first set 508 of echelettes in r-squared space.

Similar to the diffractive profile 400 shown in FIG. 4, the diffractiveprofile 500 is shown extending outward from an optical axis 502. Thediffractive profile 500 is shown relative to the Y axis 504, whichrepresents the height or phase shift of the diffractive profile 500, andis shown in units of micrometers, and may represent the distance fromthe base curve of the lens.

The height or phase shift of the diffractive profile 500 is shown inrelation to the radius on the X axis 506 from the optical axis 502.

The diffractive profile 500 includes three sets 508, 510, 512 ofdiffractive zones or echelettes. The three sets include a first set 508positioned at a central zone 514 of the lens. The second set 510 ispositioned at an intermediate zone 516 of the lens. The third set 512 ispositioned at a peripheral zone 518 of the lens. The third set 512 maybe repeated in series on the peripheral zone 518.

The first set 508 may include three diffractive zones or echelettes 520a, 520 b, 520 c, which may be connected by transition zones 522 a, 522b. The separation between the different echelettes 520 a, 520 b, 520 c,as well as the separation between the echelettes of the other sets 510,512, is indicated by the dashed step number line 524. The referencenumber 521 represents the step offset at the transition zone 522 a.

The profile of the first set 508 may be the same as the profile of thefirst set 408 shown in FIG. 4. The properties of the first set 508 maybe the same as the properties of the first set 408 shown in FIG. 4.

The second set 510 may include three diffractive zones or echelettes 528a, 528 b, 528 c, which may be connected by transition zones 530 a, 530b. The second set 510 may be adjacent to the first set 508 and may beconnected to the first set 508 with transition zone 526. The profile ofthe second set 510 in r-squared space is substantially identical to theprofile of a first set 508 of echelettes in r-squared space. The stepheights and offsets at transition zones 530 a and 530 b may be thesubstantially identical to those of respective transition zones 522 aand 522 b, and the slopes of the echelettes 528 a, 528 b, 528 c may besubstantially identical to those of the echelettes 520 a, 520 b, 520 c.

The third set 512 may include three diffractive zones or echelettes 534a, 534 b, 534 c, which may be connected by transition zones 536 a, 536b. The third set 512 may be adjacent the second set 510 and may beconnected to the second set 510 with transition zone 532.

The profile of the third set 512 may be the same as the profile of thethird set 412 shown in FIG. 4.

The third set 512 may be repeated in series on the peripheral zone 518to form a repeated set 538, similar to the repeated third set 412 shownin FIG. 4. The properties of the third set 512 and the repeated set 538may be the same as the respective third set 412 and repeated third set438 of FIG. 4.

In one embodiment, the second set 510 may be excluded, such that onlyechelettes on a central zone and echelettes on a peripheral zone may beutilized in a diffractive profile. The echelettes on the central zonemay be adjacent the echelettes on the peripheral zone.

In one embodiment, a diffractive profile may be configured such that thesecond set of echelettes in the intermediate zone has a profile that isthe same as the second set 410 of echelettes shown in FIG. 4, and afirst set of echelettes in a central zone has a profile in r-squaredspace that is substantially identical to the profile in r-squared spaceas the second set 410 of echelettes shown in FIG. 4.

The diffractive profiles disclosed herein may produce an extended rangeof vision for the patient.

The embodiments of diffractive profiles disclosed herein may bepositioned on a surface of a lens that is opposite an aspheric surface.The aspheric surface on the opposite side of the lens may be designed toreduce corneal spherical aberration of the patient.

The embodiments of diffractive profiles disclosed herein may be utilizedwith one or both surfaces of the lens that may be aspherical, or includea refractive surface designed to extend the depth of focus, or createmultifocality.

The embodiments of diffractive profiles disclosed herein may be utilizedwith a refractive zone on one or both surfaces of the lens that may bethe same size or different in size as one of the diffractive zones. Therefractive zone includes a refractive surface designed to extend thedepth of focus, or create multifocality.

Any of the embodiments of lens profiles discussed herein may be apodizedto produce a desired result. The apodization may result in the stepheights and step offsets of the repeated sets being varied according tothe apodization. The sets, however, are still considered to be repeatingsets over the optic of the lens.

A zero step height may be positioned as desired between adjacentechelettes. For example, either echelette of a set of echelettes (e.g.,two of three echelettes of a set), or all echelettes of a set ofechelettes may have a zero step height. In one embodiment, adjacent setsof echlettes may have a zero step height.

Systems and Methods for Determining Lens Shape:

FIG. 6 is a simplified block diagram illustrating a system 600 forgenerating an ophthalmic lens based on a user input.

The system 600 includes a user input module 602 configured to receiveuser input defining aspects of the user and of a lens. The input mayaccept an ophthalmic lens prescription for a patient eye. Aspects of alens may include an extended range of vision prescription, anatomicaldimensions like a pupil size performance, and lens dimensions, amongother attributes. An extended range of vision prescription can include,for example, a preferred optical power or optical power profile forcorrecting far vision and an optical power or optical power profile fornear vision. In some cases, an extended range of vision prescription canfurther include an optical power or optical power profile for correctingintermediate vision at two, or in some cases more than two intermediatefoci, which may fall between the optical powers or ranges of opticalpowers described above. A pupil size performance can include a pupilradius of a patient and the visual field to be optimized. Theseparameters can also be related to patient's life style or profession, sothat the design incorporates patient's visual needs as a function of thepupil size. Lens dimensions can include a preferred radius of the totallens, and may further include preferred thickness, or a preferredcurvature of one or the other of the anterior surface and posteriorsurface of the lens.

A multizonal diffractive surface modeling module 604 can receiveinformation about the desired lens from the user input module 602, andcan determine aspects of a multizonal lens. The multizonal diffractivesurface modeling module 604 may generate a diffractive profile based onthe ophthalmic lens prescription. For example, the modeling module 604can determine the shape of one or more echelettes of the diffractiveprofile of a diffractive multifocal lens, including the positioning,width, step height, and curvature needed to fulfill the multifocalprescription for each subset of the echelettes, as well as thepositioning of each subset of echelettes. The multizonal diffractivesurface modeling module 604 can further determine the shapes oftransition steps between echelettes. For example, transition steps maybe smoothed or rounded to help mitigate optical aberrations caused bylight passing through an abrupt transition. Such transition zonesmoothing, which may be referred to as a low scatter profile, canprovide for reductions in dysphotopsia by reducing the errantconcentration of incident light behind the lens by the transition zones.By way of further example, echelette ordering, echelette offsets, andechelette boundaries may be adjusted to adjust the step heights betweensome adjacent echelettes. In particular, the multizonal diffractivesurface modeling module can determine echelette offsets to set one ormore step heights at echelette transitions to zero, or approximatelyzero, by these or similar methods. The generated diffractive profile maybe any of the diffractive profiles disclosed in this application.

The multizonal diffractive surface modeling module 604 can be configuredto generate performance criteria 612, e.g. via modeling opticalproperties in a virtual environment. Performance criteria can includethe match of the optical power profile of the multizonal lens with thedesired optical power profile based on the extended range of visionprescription. The performance criteria can also include the severity ofdiffractive aberrations caused by lens surface. In some cases, themultizonal surface modeling module 604 can provide a lens surface to alens fabrication module for facilitating the production of a physicallens, which can be tested via a lens testing module 610 for empiricallydetermining the performance criteria 612, so as to identify opticalaberrations and imperfections not readily discerned via virtualmodeling, and to permit iteration. The lens fabrication module maycomprise a manufacturing assembly that may fabricate the ophthalmic lensbased on the diffractive profile.

A refractive surface modeling module 606 can receive information fromthe user input 602 and multizonal surface modeling modules 604 in orderto determine refractive aspects of the lens. For example, provided withan extended range of vision prescription and a set of diffractive powersthat can be generated by a diffractive profile, the refractive surfacemodeling module 606 can provide a refractive geometry configured toprovide a base power which, when combined with the diffractive surface,meets the requirements of the extended range of vision prescription. Therefractive surface modeling module 606 can also generate performancecriteria 612, and can contribute to providing a lens surface to a lensfabrication module 608 for facilitating the production of the physicallens.

FIG. 7 is an example process 700 for generating a diffractive lenssurface, in accordance with embodiments. The process 700 may beimplemented in conjunction with, for example, the system 600 shown inFIG. 6. Some or all of the process 700 (or any other processes describedherein, or variations, and/or combinations thereof) may be performedunder the control of one or more computer systems configured withexecutable instructions and may be implemented as code (e.g., executableinstructions, one or more computer programs, or one or moreapplications) executing collectively on one or more processors, byhardware or combinations thereof. The code may be stored on acomputer-readable storage medium, for example, in the form of a computerprogram comprising a plurality of instructions executable by one or moreprocessors. The computer-readable storage medium may be non-transitory.

The process 700 may include a method of designing an intraocular lensand may include receiving an input of an ophthalmic lens prescriptionfor a patient eye, which may be an extended range of vision lensprescription (act 702). The input can include, e.g., a desired opticalpower profile for correcting impaired distance vision, a desired opticalpower profile for correcting impaired intermediate distance vision, adesired optical power profile for accommodating near vision, and anysuitable combination of the above. Based on a desired optical powerprofile, a diffractive profile can be defined and generated including acentral zone, a peripheral zone, and an intermediate zone positionedbetween the central zone and the peripheral zone. The generateddiffractive profile may include a central zone including a first set ofthree echelettes arranged around the optical axis, the first set havinga profile in r-squared space (act 704). The generated diffractiveprofile may include an intermediate zone including a second set of threeechelettes arranged around the optical axis, the second set having aprofile in r-squared space that is different than the profile of thefirst set (act 706). The generated diffractive profile may include aperipheral zone including a third set of three echelettes arrangedaround the optical axis, the third set having a profile in r-squaredspace that is different than the profile of the first set and theprofile of the second set, the third set being repeated in series on theperipheral zone (act 708).

In one embodiment, a diffractive profile may be generated and utilizedthat includes a central zone and a peripheral zone. The central zone mayinclude a first set of three echelettes arranged around the opticalaxis, the first set having a profile in r-squared space. The peripheralzone may include a second set of three echelettes arranged around theoptical axis, the second set having a profile in r-squared space that isdifferent than the profile of the first set. The second set may berepeated in series on the peripheral zone.

In one embodiment, the diffractive profile may include an intermediatezone positioned between the central zone and the peripheral zone. Theintermediate zone may include a third set of three echelettes arrangedaround the optical axis, the third set having a profile in r-squaredspaced that is substantially identical to the profile of the first set(in the central zone).

The diffractive lens profile of the multizonal diffractive lens surfacemay be used in combination with a known refractive base power. To thatend, a refractive lens surface may be generated having a base powerthat, in combination with the diffractive lens surface generated basedon the diffractive profile, meets the extended range of vision lensprescription (act 710). A total lens surface can be generated based onboth the refractive lens surface and the diffractive lens surface (act712). The refractive lens surface can include a refractive lenscurvature on the anterior surface of the lens, the posterior surface ofthe lens, or both. Instructions can be generated to fabricate anintraocular lens based on the generated total lens surface (act 714). Amanufacturing assembly may fabricate the ophthalmic lens based on theinstructions. The methods herein are not limited to the examples ofdiffractive profiles discussed here, and may extend to any of thediffractive lens profiles and ophthalmic lenses disclosed in thisapplication.

Computational Methods:

FIG. 8 is a simplified block diagram of an exemplary computingenvironment 800 that may be used by systems for generating thediffractive profiles and ophthalmic lenses of the present disclosure.Computer system 822 typically includes at least one processor 852 whichmay communicate with a number of peripheral devices via a bus subsystem854. These peripheral devices may include a storage subsystem 856comprising a memory subsystem 858 and a file storage subsystem 860, userinterface input devices 862, user interface output devices 864, and anetwork interface subsystem 866. Network interface subsystem 866provides an interface to outside networks 868 and/or other devices, suchas the lens fabrication module 608 or lens testing module 610 of FIG. 6.

User interface input devices 862 may include a keyboard, pointingdevices such as a mouse, trackball, touch pad, or graphics tablet, ascanner, foot pedals, a joystick, a touchscreen incorporated into thedisplay, audio input devices such as voice recognition systems,microphones, and other types of input devices. User input devices 862will often be used to download a computer executable code from atangible storage media embodying any of the methods of the presentdisclosure. In general, use of the term “input device” is intended toinclude a variety of conventional and proprietary devices and ways toinput information into computer system 822.

User interface output devices 864 may include a display subsystem, aprinter, a fax machine, or non-visual displays such as audio outputdevices. The display subsystem may be a cathode ray tube (CRT), aflat-panel device such as a liquid crystal display (LCD), a projectiondevice, or the like. The display subsystem may also provide a non-visualdisplay such as via audio output devices. In general, use of the term“output device” is intended to include a variety of conventional andproprietary devices and ways to output information from computer system822 to a user.

Storage subsystem 856 can store the basic programming and dataconstructs that provide the functionality of the various embodiments ofthe present disclosure. For example, a database and modules implementingthe functionality of the methods of the present disclosure, as describedherein, may be stored in storage subsystem 856. These software modulesare generally executed by processor 852. In a distributed environment,the software modules may be stored on a plurality of computer systemsand executed by processors of the plurality of computer systems. Storagesubsystem 856 typically comprises memory subsystem 858 and file storagesubsystem 860. Memory subsystem 858 typically includes a number ofmemories including a main random access memory (RAM) 870 for storage ofinstructions and data during program execution and/or a read only member(ROM) 882.

Various computational methods discussed above, e.g. with respect togenerating a multizonal lens surface, may be performed in conjunctionwith or using a computer or other processor having hardware, software,and/or firmware. The various method steps may be performed by modules,and the modules may comprise any of a wide variety of digital and/oranalog data processing hardware and/or software arranged to perform themethod steps described herein. The modules optionally comprising dataprocessing hardware adapted to perform one or more of these steps byhaving appropriate machine programming code associated therewith, themodules for two or more steps (or portions of two or more steps) beingintegrated into a single processor board or separated into differentprocessor boards in any of a wide variety of integrated and/ordistributed processing architectures. These methods and systems willoften employ a tangible media embodying machine-readable code withinstructions for performing the method steps described above. Suitabletangible media may comprise a memory (including a volatile memory and/ora non-volatile memory), a storage media (such as a magnetic recording ona floppy disk, a hard disk, a tape, or the like; on an optical memorysuch as a CD, a CD-R/W, a CD-ROM, a DVD, or the like; or any otherdigital or analog storage media), or the like.

What is claimed is:
 1. An ophthalmic lens, comprising: a first surfaceand a second surface disposed about an optical axis; and a diffractiveprofile imposed on one of the first surface or the second surface, thediffractive profile including a central zone, a peripheral zone, and anintermediate zone positioned between the central zone and the peripheralzone, wherein: the central zone includes a first set of threediffractive echelettes arranged around the optical axis, the first sethaving a profile in r-squared space; the intermediate zone includes asecond set of three diffractive echelettes arranged around the opticalaxis, the second set having a profile in r-squared space that isdifferent than the profile of the first set; and the peripheral zoneincludes a third set of three diffractive echelettes arranged around theoptical axis, the third set having a profile in r-squared space that isdifferent than the profile of the first set and the profile of thesecond set, the third set being repeated in series on the peripheralzone.
 2. The lens of claim 1, wherein each of the three diffractiveechelettes of the first set have a different profile than each other inr-squared space.
 3. The lens of claim 2, wherein each of the threediffractive echelettes of the second set have a different profile thaneach other in r-squared space.
 4. The lens of claim 3, wherein each ofthe three diffractive echelettes of the third set have a differentprofile than each other in r-squared space.
 5. The lens of claim 1,wherein the third set being repeated in series on the peripheral zoneforms a repeated set that is configured to result in a lightdistribution with more than 40% of incident light distributed toward afirst diffractive power, less than 10% of incident light distributedtoward a second diffractive power, less than 10% of incident lightdistributed toward a third diffractive power, and more than 10% ofincident light distributed toward a fourth diffractive power.
 6. Thelens of claim 5, wherein the second diffractive power is between about0.58 and 1.5 diopter, the third diffractive power is between about 1.17and 3 diopter, and the fourth diffractive power is between about 1.75and 4.5 diopter.
 7. The lens of claim 1, wherein the profile of thefirst set includes a zero step height between two of the threediffractive echelettes of the first set.
 8. The lens of claim 7, whereinthe three diffractive echelettes of the first set include a firstdiffractive echelette, a second diffractive echelette, and a thirddiffractive echelette, with the third diffractive echelette beingpositioned radially outward from the first diffractive echelette, andthe second diffractive echelette being positioned between the firstdiffractive echelette and the third diffractive echelette, and the zerostep height being between the second diffractive echelette and the thirddiffractive echelette.
 9. The lens of claim 1, wherein the profile ofthe third set includes a zero step height between two of the threediffractive echelettes of the third set.
 10. The lens of claim 9,wherein the three diffractive echelettes of the third set include afirst diffractive echelette, a second diffractive echelette, and a thirddiffractive echelette, with the third diffractive echelette beingpositioned radially outward from the first diffractive echelette, andthe second diffractive echelette being positioned between the firstechelette and the third diffractive echelette, and the zero step heightbeing between the second diffractive echelette and the third diffractiveechelette.
 11. The lens of claim 1, wherein the three diffractiveechelettes of the first set include a first diffractive echelette, asecond diffractive echelette, and a third diffractive echelette, andwherein the first diffractive echelette begins at the optical axis ofthe lens and extends radially outward from the optical axis.